 Ascendency can thus be regarded as a refinement of Lotka's supposition that also takes into account how power is actually being channeled within a system.In mathematical terms, ascendency is the product of the aggregate amount of material or energy being transferred in an ecosystem times the coherency with which the outputs from the members of the system relate to the set of inputs to the same components (Ulanowicz 1986).Coherence is gauged by the average mutual information shared between inputs and outputs (Rutledge et al.